1. Field of the Invention
This invention relates generally to heating and air conditioning systems and, more particularly, to a solid state heating and air conditioning system employing thermoelectric modules.
2. Description of the Prior Art
As is well-known, the costs associated with heating and cooling the interior of a structure such as a residence, office, etc. are increasing dramatically due to the current energy shortages. The conventional freon-pumped systems suffer from several disadvantages. First, both the initial costs of manufacture and installation are high. Second, such systems are expensive to operate and maintain. Third, the conventional systems are complex and require many moving parts. As a result, maintenance is often a problem. Another disadvantage resides in the fact that standard central heating/air conditioning systems generally operate off a single thermostat and therefore cannot maintain individual room temperatures. Finally, it is well-known that freon is detrimental to the Earth's ozone layer.
In a thermoelectric cooling system, a cold junction is produced where heat is absorbed by electrons while moving from a lower energy state to a higher energy state. A power supply provides the energy required to move the electrons through the energy state system. A heat exchanger is attached to a hot junction to expel excess heat.
Thermoelectric cooling "couples" are made from two elements of semiconductor material, primarily Bismuth Telluride, heavily doped to create an excess (N-type) or a deficiency (P-type) of electrons. Heat absorbed at a cold junction is pumped to a hot junction at a rate proportional to the current passing through the "couple". In practical applications, a plurality of couples are combined in a module where they are connected in series electrically and in parallel thermally. Such modules are commercially available from Material Electronic Products Corporation, Trenton, N.J.
The use of such thermoelectric heat pumps has thus far been limited to situations arising out of special considerations such as size, space, weight, environmental conditions, etc. For example, a typical unit measures one inch by one inch by 0.25 inches thick. Use may be found in military and aerospace applications, laboratory and scientific equipment, mobile refrigerators such as recreational vehicle refrigerators and mobile home refrigerators, portable picnic coolers, cream and butter dispensers, beverage coolers, etc.